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Patented Apr. 2, 1929.

UNITED STATES ROY J. WINSOR, OF BUCYRUS, OHIO.

TRACK.

Application filed April 22, 1925. Serial No. 24,999.

My present invention relates to tractors, and more particularly to animproved tractor tread of the crawler type.

Where it is desired to use tractors of the crawler type in certainsituations as, for example, in uneven or swampy ground, some means mustbe devised for preventing the upward sagging of the lower reach of thecrawler tread while enabling the track to be flexed to allow the same topass over the sprockets or other circular members at the ends. Variousexpedients have been suggested and provided for utilizing tractors ofthe crawler type in these situations, none of which, so far as I amaware, have been entirely successful or satisfactory. Where the tractortread has been self-supporting or, what is termed in the trade, rigid,it has usually been so rigid as to preclude its propel functioning, andwhere the proper degree of flexibility has been given to such'track, thetrack has failed to function for this reason alone.

A serious defect in such tracks is the 010g ging up of the variousjoints by grit or mud and such clogging up prevents, after a very shorttime, the free running of the track over the sprockets or other circularmembers on which they arecarried, and. throws the various elements ofthe track so far out of alignment with each other as to cause the sameto jump off the circular members over which the tracks run.

In my present invention I have endeavored to obviate the objections toprior devices and as above pointed out and have produced aself-supporting track'or rigid track memher in which the track, afterbeing assembled, is self-supporting and in which the lower reach thereofwill not sag upward, and further, such tIZICi is extremely flexible inpassing over the rollers or sprockets and the joints are so constructedasto be practlcally self-cleaning. Further, the construction of thetrack elements is such that the elements are subjected to the leastpossible wear and no wear comes on the track elements themselvesbecauseof thepiv-otal joint connections, all wear being taken up iby insertedsteel bushings or pins-which may be readily removed and renewed.

In tractors employing tracks of the crawler type, the trackengages withthe ground and supports the load carried by the. tractor.

WVith an extremely heavy load, it is essential that a considerableportion, if not the entire length, of the lower reach of the track be inengagement with the ground, this for the purpose of obtaining thenecessary traction. \Vhen, however, the tractor is carrying only alightload, it is only necessary that arelatively small portion of the lowerreach of the track be in engagement with the ground as sufiicienttraction will be obtained thereby and any other traction in excess ofthat required is merely consuming power needlessly. In my presentinvention, therefore, I have devised a means for attaching the track tothe crawler whereby a portion of the load of the'tractor is held by thelower reach of the track, and as the load is increased, the lower reachof the track is flattened out and is gradually brought more nearly intoa horizontal plane or into a position in engagement with the groundasthe load is increased. I believe this to be an entirely new feature intrack construction and therefore desire to claim the same broadly.

The principal object of my invention, therefore, is an improved track ofthe crawler type. V

Another object of the invention is a selfsupporting track in which wearis reduced to a minimum and which is capable of eliicient operation onuneven or marshy ground.

A further objectof the invention is an improved meansfor attaching anendless I rack to a tractor whereby the weight of the tractor is carriedby thc lower reach of the trac tor.

In the accompanying drawings illustrating the preferredembodiment of myinvention,

Fig. 1 is a front elevation of the complete track in position on atractor; I

Fig. 2 isan inn-er plan view of a plurality of track elements inassembled position, a portion being shown in section;

Fig. 3 is a side elevation of F ig; 2, a portion thereof being shown insection;

Fig. 4 is an outer plan viewof Fig. 3;

Fig. 5 is a perspective view of one of the track elements, and j I Fig.6 is a perspective view of another of the track elements.

Referring to the drawings, there is illustrated a track designated as anentirety by the numeral 10 in Fig. .1, this track being mounted onsprockets 11 secured to an axle 12 rotatably mounted in bearing blocks13 and therefore the shafts 1.2, outward from each other whilemaintaining the same parallel. Centrally located with respect to thebolster 5 and on the under side thereof is a vertical slot 18 in whichis slidably mounted, for vertical movement, a member 19. This men'iber19 has arranged at its lower end and at each side thereof shafts 20,these shafts being rotatably moiu'ited in the member and secured on theshafts 20 are sprockets 21 which engage with the upper or inner face ofthe lower reach of the track members forming the track 10. Between theupper end of the member 19 and the under face of the slot 18 is arrangeda heavy coil spring 22 and this construction provides for a springsuspension on the bolster 15 of the top of the member 19. On either sideof the member 19 are upwardly extending shafts or rods 23 which slideupward in vertical holes in the bolster 15. Surrounding the rods orshafts 23 and lying between the under face of the bolster 15 and themember 18 are coil springs 21, such springs being relatively light ascompared with the spring 22. At the upper end ofthe member 19 is abearing in which is rotatably mounted a main shaft 25, this shaftextending transversely of the tractor mechanism, such mechanism beingindicated generally by the reference numeral 26. Secured to the shaft 25is a driving sprocket 27 in line with a sprocket 28 secured to theforward one of the shafts 12 and over the sprockots 27 and 28 runs adriving chain 29 and by means of which the shafts 12 are rotated.

Referring now particijilarly to Figs. 2-6

inclusive, the track 10 is comprised of a plurality of members 30 and 31arrangei'l alternately. The member 30 is composed of a rectangular plate32 of any desired dimensions, and formed integral therewith and 0X-tending upwardly therefrom is a base on each end of which is formedparallelly arranged spaced lugs or cars 3 1. The lugs or cars 34; aredrilled, as indicated at 35, at each end, the drilled holes 35 being inalignment with each other at each end of the member 3 1. Secured to themember 32 on the face thereof opposite the face on which is the mem her33 a plate or spud36, this plate being secured, preferably, by riveting,as indicated at 87, or in any other desired manner. Preferably the plate36 has the form shown in the drawings, although this form may be variedas desired. I lind this form preferable, however, as it is a commericalform of striiicture and is easily and economically faln'icaterl. Iurther, the form is such that thereinay be secured thereto rubber facesor blocks 38, as indicated in dottedlines in Fig.

The distance apart of the holes 35 in the lug 341; may be any distancedesired, such dis tance determining the pitch of the track.

Referring now to Fig. 6 particularly, it will be noted. that the elementcomprises a plate 39 substantially rectangular in form, and formed onthe upper face thereof is a member 10 provided at each end withparallely arranged spaced lugs l1. The distance between the outer facesof the lugs 11 is slightly less than the distance between the innerfaces of the lugs on the member 30. The ends of the lugs 10 are drilledto re ceive as a press it a hardened steel bushing 42, the hole throughsuch bushing 12 being substantially equal to the diameter of the holes35 in the lugs Before the bushings 12 are pressed into position, thereplaced thereover a bushing 1-3 which is freely rotatable on the bushing41-2. The bushin 13 are engaged by the teeth of the sprockets 11. Innbling the members If and 31 to form the track 10, the men'ibers 31 arefirst assembled as ab iive described and one end thereof placed inposition within the lugs and the pin 1% is passed through the holes 35and through the holes in the bushings a2 and riveted solidly to the lugs31. it will thus be seen that the wear due to the flexing of the attached members 30 and 31 acts on the pin 14: and on the inner bushing 42while the wear occasioned by the teeth of the sprockets 11 acts on theroller bushings 43. There is, therefore, no wear on either the lugs 34or the lugs 41-1. lVhen, therefore, it is necessary to repair the tracl:because of looseness of the oints, it is merely necessary to drive outthe pin 14', replace the bushing 12, insert a new bushing 42 and rivetanew pin 44 in position in the lugs 3:1. Referring now to Fig. 3, itwill be noted that the ends of the substantially rectangular member 39rest on the ends of the rectangular member 32 and this constructionprovides a track wvhieh will. not buckle upward beyond the horizontalposition shown in such Fig. 3.

The track 10 having been assembled from a plurality of elements 30 and31, as above dcscril'ied, and placed in position on the sprockets 11with the sprockets 21 in position to engage with the roller bushings 1-3on the lower reach of the track, as shown in Fig. 1, it will be seenthat, with no load or a light load on the tractor 26, the resiliency ofthe springs 22 and 28 will he sutiiic'ent to force the lower reach ofthe track 10 downwardly at its center and it assumes an arcuate formwith a small portion only in engagement with the ground. Further, itwill obvious that, with no load or a light load on the tractor 26, theload is carried on the springs 22 and '23 and that the bolsters 15 donot at this time carry any of the loac iVhen, however, the load onrthetractor 26 13 increased to such a point that the resiliency of thesprings 22 and 23 is completely overcome, the upper end of the member 19will be brought into its uppermost position toward the upper end of theslot 18 in the bolster 15 and the lower reach of the track 10 will beflattened out so that more of it will come into engagement with theground, and at this time it will be apparent that the load on thetractor 26, as well as the tractor itself, is being supported directlyby the bolster 15. WVith my improved construction, a self-supporting,rigid track or rail is produced and in which a light load is springsuspended while a heavy load is carried directly on the rigid bolstertractor 15. This construction eliminates to a con 'siderable extent thewear heretofore deemed necessary in prior constructions and makes for adevice that is efficient and long lived. Further, this method of springsuspension of the tractor under no, or light, load enables the tractorto be driven insuch condition at a relatively high speed without unduewear taking place in the mechanism.

l/Vhile I have necessarily shown and described the pret'erred embodimentof my invention somewhat in detail, it is to be understood that I mayvary the size, shape, and arrangement of part-s within wide limitswithout departing from the spirit of the invention.

Having thus described my invention, what I claim as new is:

An improved track comprising a plurality of two diflerent elementsarranged alternately, one of said elements comprising a rectangularplate, a base formed integral therewith and having formed at each end aplurality of parallelly arranged lugs, the second of said elements beingcomposed of a rectangular plate having a base formed integral therewith,and having at each end parallelly arranged lugs, a plurality of pairs ofalined perforations in said lugs, shafts GX- tending through the lugs insaid first said elements and through the aligned perforation in thesecond said elements, the outer face oi the rectangular plate on thesecond ele ment engaging with the inner face of the rectangular plate ofthe first element, whereby pivotal movement of the elements with respectto each other takes place in one direction only from the rectangularplate.

In testimony whereof, I have signed my name to this specification.

I ROY J. WINSOR.

